Human-caused climate change is altering the habitat of Adélie penguins (Pygoscelis adeliae). In an article recently published in PLOS ONE, a team of researchers led by Amélie Lescroël from the Centre d'Ecologie Fonctionnelle et Evolutive (CNRS) in France, found that changes in sea-ice content and newly formed icebergs significantly impacted Adélie penguin communities in the Ross Sea.

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Climate change is leading to major shifts in sea ice. One of the largest glaciers in Antarctica has begun to melt at a rate some scientists describe as irreversible. Pine Island Glacier contributes a fourth of the discharge of the West Antarctic Ice Sheet. It is estimated that if this entire ice sheet were to melt, sea levels would rise by ten feet. Other areas of the Antarctic are experiencing cooling events, resulting in greater ice coverage known as "fast ice." However, scientists believe that melting will supplant fast ice in the near future.

"While net sea ice cover (i.e., the area of ocean covered by ice) has increased over the past few decades [in Antarctica] owing to wind changes brought largely by mid-latitude warming and the Antarctic Ozone Hole, modeled predictions point to a decrease by 5-15 percent, depending on sector, by 2025-2052," the study states. "Concomitantly, increased ice shelf instability will lead to more frequent iceberg calving, including very large icebergs (hundreds of square kilometers)."

Sea ice cover variability directly affects Adélie habitat, and the species' ability to adjust to this variability will determine their future.

Adélie penguins depend on sea-ice for foraging, resting, molting, breeding and migrating. They are one of only two penguin species that depend on sea ice and not icebergs, the other being the Emperor penguin (Aptenodytes forsteri).

"This 'dependence' is actually a manifestation of them being the only penguin species that are able to cope with sea ice," Lescroël told mongabay.com.

To a certain extent, Adélie penguins are adapted to cope with changes in their habitat. For instance, they're able to easily gain and lose fat depending on ice conditions, and dive for longer periods of time compared to other penguin species.

"They dive mostly between 10 and 50 meters deep to catch their prey but can dive up to 180 meters, which is a world record," said Lescroël.